config_preempt_RT patch platform support question.

config_preempt_RT patch platform support question.

[Amir Aharon]

Hi,
I work on a project which delivers low latency audio streaming via a Linux machine. I receive/send audio frames of 4 samples each per network frame (raw Ethernet) so I expect to have a network interrupt each 90 microseconds.
I use Linux 2.6.26.3-rt7 on different platforms; unfortunately we encountered problems such as kernel panics, depend on the platform running...

My questions are:
How can I have more details on the tests which where used to evaluate the platform running the config_preempt_RT (specifically on networking issues)? 
Does Intel Q6600 2.4GHz (quad core) has been tested? Are there known issues?
Does Xeon x5482 3.2GHz (x2 meaning octa core) has been tested? Are there known issues?


Thanks,
Amir.

Re: config_preempt_RT patch platform support question.

[Carsten Emde]

Amir,

> I work on a project which delivers low latency audio streaming via a
> Linux machine. I receive/send audio frames of 4 samples each per
> network frame (raw Ethernet) so I expect to have a network interrupt
> each 90 microseconds. I use Linux 2.6.26.3-rt7 on different
> platforms; unfortunately we encountered problems such as kernel
> panics, depend on the platform running...
The PREEMPT_RT patches for kernel 2.6.26 are still under development.
Please post the various kernel messages you are observing. BTW: The most
recent 2.6.26 patch is 2.6.26.6-rt11.

> My questions are: How can I have more details on the tests which
> where used to evaluate the platform running the config_preempt_RT
> (specifically on networking issues)? Does Intel Q6600 2.4GHz (quad
> core) has been tested? Are there known issues? Does Xeon x5482 3.2GHz
> (x2 meaning octa core) has been tested? Are there known issues?
For the time being, linux-2.6.24.7-rt21 is believed to be stable and
ready for production. This version has been tested heavily under x86
(slow/fast machines, single/dual/quad core, 32/64 bit) and under various
PPC platforms. It has been tested less heavily on ARMs and MIPSes. There
are no known issues on x86 platforms. Would you mind to run
2.6.24.7-rt21 on your machines?

	Carsten.

RE: config_preempt_RT patch platform support question.

[Amir Aharon]

Here is the kernel dump:
[] post_schedule_rt
[] finish_task_switch
[] __schedule
[] check_preempt_curr_rt
[] try_to_wake_up
[] wake_up_process
[] e1000_intr_msi
[] handle_IRQ_event
[] preempt_schedule
[] do_irqd
[] do_irqd
[] kthread
[] kthread
[] kernel_thread_helper

EIP: push_rt_task
 Node: IRQ-217[1433] exited with preempt_count 2


I have got this when I run my app on octa core xeon (Xeon x5482 3.2GHz).

I'll run my app with linux-2.6.24.7-rt21 during the weekend and see where it goes...

Thanks,
Amir.


-----Original Message-----
From: Carsten Emde [mailto:Carsten.Emde@osadl.org] 
Sent: Thursday, November 13, 2008 9:42 AM
To: Amir Aharon
Cc: RT-Users
Subject: Re: config_preempt_RT patch platform support question.

Amir,

> I work on a project which delivers low latency audio streaming via a
> Linux machine. I receive/send audio frames of 4 samples each per
> network frame (raw Ethernet) so I expect to have a network interrupt
> each 90 microseconds. I use Linux 2.6.26.3-rt7 on different
> platforms; unfortunately we encountered problems such as kernel
> panics, depend on the platform running...
The PREEMPT_RT patches for kernel 2.6.26 are still under development.
Please post the various kernel messages you are observing. BTW: The most
recent 2.6.26 patch is 2.6.26.6-rt11.

> My questions are: How can I have more details on the tests which
> where used to evaluate the platform running the config_preempt_RT
> (specifically on networking issues)? Does Intel Q6600 2.4GHz (quad
> core) has been tested? Are there known issues? Does Xeon x5482 3.2GHz
> (x2 meaning octa core) has been tested? Are there known issues?
For the time being, linux-2.6.24.7-rt21 is believed to be stable and
ready for production. This version has been tested heavily under x86
(slow/fast machines, single/dual/quad core, 32/64 bit) and under various
PPC platforms. It has been tested less heavily on ARMs and MIPSes. There
are no known issues on x86 platforms. Would you mind to run
2.6.24.7-rt21 on your machines?

	Carsten.

RE: config_preempt_RT patch platform support question.

[Amir Aharon]

Hi Carsten,

Good new - 2.6.24.7-rt21 works perfectly on my Xeon x5482 3.2GHz, could not reproduce any of the kernel panic I had.

Thanks for the tip.
 

-----Original Message-----
From: linux-rt-users-owner@vger.kernel.org [mailto:linux-rt-users-owner@vger.kernel.org] On Behalf Of Amir Aharon
Sent: Thursday, November 13, 2008 3:00 PM
To: Carsten Emde
Cc: RT-Users
Subject: RE: config_preempt_RT patch platform support question.

Here is the kernel dump:
[] post_schedule_rt
[] finish_task_switch
[] __schedule
[] check_preempt_curr_rt
[] try_to_wake_up
[] wake_up_process
[] e1000_intr_msi
[] handle_IRQ_event
[] preempt_schedule
[] do_irqd
[] do_irqd
[] kthread
[] kthread
[] kernel_thread_helper

EIP: push_rt_task
 Node: IRQ-217[1433] exited with preempt_count 2


I have got this when I run my app on octa core xeon (Xeon x5482 3.2GHz).

I'll run my app with linux-2.6.24.7-rt21 during the weekend and see where it goes...

Thanks,
Amir.


-----Original Message-----
From: Carsten Emde [mailto:Carsten.Emde@osadl.org] 
Sent: Thursday, November 13, 2008 9:42 AM
To: Amir Aharon
Cc: RT-Users
Subject: Re: config_preempt_RT patch platform support question.

Amir,

> I work on a project which delivers low latency audio streaming via a
> Linux machine. I receive/send audio frames of 4 samples each per
> network frame (raw Ethernet) so I expect to have a network interrupt
> each 90 microseconds. I use Linux 2.6.26.3-rt7 on different
> platforms; unfortunately we encountered problems such as kernel
> panics, depend on the platform running...
The PREEMPT_RT patches for kernel 2.6.26 are still under development.
Please post the various kernel messages you are observing. BTW: The most
recent 2.6.26 patch is 2.6.26.6-rt11.

> My questions are: How can I have more details on the tests which
> where used to evaluate the platform running the config_preempt_RT
> (specifically on networking issues)? Does Intel Q6600 2.4GHz (quad
> core) has been tested? Are there known issues? Does Xeon x5482 3.2GHz
> (x2 meaning octa core) has been tested? Are there known issues?
For the time being, linux-2.6.24.7-rt21 is believed to be stable and
ready for production. This version has been tested heavily under x86
(slow/fast machines, single/dual/quad core, 32/64 bit) and under various
PPC platforms. It has been tested less heavily on ARMs and MIPSes. There
are no known issues on x86 platforms. Would you mind to run
2.6.24.7-rt21 on your machines?

	Carsten.
--
To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

few question about the platform tested and in use with config_preempt_rt...

[Amir Aharon]

Hi all,

I have few questions regarding the platform tested with the config_preempt_rt:

1. When was last time the table at <http://rt.wiki.kernel.org/index.php/CONFIG_PREEMPT_RT_Patch> updated?

2. Was the worse case latency measured under stress? If so which stress test was used? 

3. What kind of network tests has been used? Does the worse case latency valid for network application (RT low latency audio streaming)?

3. Were there any additional hardware tweaking done on the tested system (e.g. bios option tweaking such as turning off fan control)?

4. Were there any additional kernel option tweaking done, e.g. - clock source, tick-less kernel?

5. Which kernel modules were loaded on the measured system (USB module, keyboard controller, Ethernet driver etc...)?

6. What bios version was used? Was it the latest version?

7. Could you share the contents of /proc/interrupts file of the tested system?

Thanks,
Amir.

Did anyone tested core i7?

[Amir Aharon]

Hi,
Did anyone tested linux-2.6.24.7-rt21 on the new Intel core i7 ?